1. Field of the Invention
The present invention relates to a light emitting diode (LED), and more particularly, to a hybrid LED chip which facilitate to improve an optical efficiency by enhancing a current injection property, and an LED device including the hybrid LED chip. Also, the present invention relates to a method for manufacturing the hybrid LED chip, which facilitates to improve a manufacturing efficiency by omitting a wire bonding process.
2. Discussion of the Related Art
A light emitting diode (LED) is widely used in various fields owing to advantageous properties of low power consumption and long lifespan. Especially, a white-color LED device is recently applied to an illumination device, and a backlight for a display device.
FIG. 1 illustrates a related art LED device.
Referring to FIG. 1, the related art LED device comprises an LED chip 10 for generating light with a specific wavelength; a fluorescent layer 50 for converting the light generated in the LED chip 10 into specific colored light; a lead electrode 30 for supplying a driving power source to the LED chip 10; a bonding wire (generally, gold wire) 20 for electrically connecting the LED chip 10 and the lead electrode 30 with each other; a lead frame 40 for mounting the LED chip 10, the fluorescent layer 50, and the lead electrode 30 thereon; and a lens 60 on the fluorescent layer 50.
For improvement of optical efficiency in the LED device, various conditions have to be considered. Among the things considered to be important is optical efficiency of the LED chip 10 for generating the light.
The LED chip 10 may be largely classified into a lateral type and a vertical type.
FIG. 2 illustrates a related art lateral type LED chip; and FIG. 3 illustrates a related art vertical type LED chip.
As shown in FIG. 2, the related art lateral type LED chip comprises an n-type first clad layer (n-GaN) of n-GaN material on a sapphire substrate or silicon (SiC) substrate; a multiple quantum well layer (MQW layer); a p-type second clad layer (p-GaN) of p-GaN material; a bonding metal layer for bonding of P-type electrode; and the P-type electrode. At one side of the first clad layer, there are the MQW layer, second clad layer, bonding metal layer, and P-type electrode which are sequentially formed on the first clad layer.
At the other side of the first clad layer, a bonding metal layer for bonding of N-type electrode and the N-type electrode are sequentially formed on the first clad layer.
FIG. 2 illustrates that the n-type first clad layer (n-GaN), the MQW layer, and the p-type second clad layer (p-GaN) are sequentially formed on the sapphire substrate.
Like the aforementioned lateral type LED chip, the related art vertical type LED chip comprises an n-type first clad layer (n-GaN) of n-GaN material, a multiple quantum well layer (MQW layer), and a p-type second clad layer (p-GaN) of p-GaN material, which are sequentially formed on a sapphire substrate or silicon (SiC) substrate.
The vertical type LED chip is different from the lateral type LED chip of FIG. 2 in that the vertical type LED chip includes P-type electrode and N-type electrode provided in a vertical structure. FIG. 3 illustrates that the n-type first clad layer (n-GaN), the MQW layer, and the p-type second clad layer (p-GaN) are sequentially formed on the sapphire substrate.
In the related art lateral type LED chip and vertical type LED chip, the P-type electrode and N-type electrode are electrically connected with the lead electrode 30 of FIG. 1 through the bonding wire 20, whereby the driving power source is applied to the P-type electrode and N-type electrode.
Thus, the bonding wire 20 is essential for driving of the LED device. That is, it is disadvantageous in that the process for forming the bonding wire 20 is necessarily carried out for the manufacturing process.
The bonding wire 20 having a fine line-width may cause the deterioration of current injection property to the LED chip 10, and simultaneously the defective connection between the bonding wire 20 and the lead electrode 30.
If the defects occur due to the connection of the bonding wire 20, the LED device cannot emit the light, whereby reliability and quality of the LED device is lowered.
Also, since the aforementioned lateral type LED device includes the P-type electrode and N-type electrode provided in a horizontal direction, a current flowing in the horizontal direction from the N-type electrode to the P-type electrode via the MQW layer becomes narrow, to thereby cause the deterioration of optical efficiency.
Also, the aforementioned lateral type LED device has a problem of low heat dissipation due to its structural property, whereby reliability and quality of the LED device is lowered.